// v1.3 - Normal version

// Task 1: Reach a certain speed; Task 2: Bounce off walls
var task1 = 145, task1_submitted;
var task2 = 1000, task2_submitted;

// Variables
var power, xspeed, yspeed, friction, gravity, thrust, update_timer, speed, bounces;
var velocity_start = 1;

// Initialization
function onLoad() {
    // Textfield
    _root.speed_textfield.textColor = 0xFFFFFF;
    _root.speed_textfield._x = 15;
    _root.speed_textfield._y = 15;

    // Physic engine
    friction = 0.9685;
    gravity = 0.1155;
    thrust = 0.7395;
    power = 0.3285;
    xspeed = 0;
    yspeed = 15;
    circle._x = 300;
    circle._y = 100;
}

function submitTask1() {
    // Submit
    task1_submitted = true;
}

function submitTask2() {
    // Submit
    task2_submitted = true;
}

function updateSpeed() {
    speed = Math.sqrt((yspeed * yspeed) + (xspeed * xspeed));
    speed = int((speed * 100) / 100);
    if ((speed >= task1) && (not task1_submitted)) {
        submitTask1();
    }
}

function updateBounces() {
    if ((not task2_submitted) && (bounces >= task2)) {
        submitTask2();
    }
}

circle.onEnterFrame = function() {
    // Increase speed
    if (Key.isDown(Key.RIGHT)) {
        xspeed += power;
    }
    if (Key.isDown(Key.LEFT)) {
        xspeed -= power;
    }
    if (Key.isDown(Key.UP)) {
        yspeed -= power * thrust;
    }
    if (Key.isDown(Key.DOWN)) {
        yspeed += power / thrust;
    }
    // Decrease speed
    if ((not Key.isDown(Key.RIGHT)) && (not Key.isDown(Key.LEFT))) {
        xspeed *= friction;
    }
    if ((not Key.isDown(Key.UP)) && (not Key.isDown(Key.DOWN))) {
        yspeed *= friction;
    }
    // Movement
    circle._rotation += xspeed;
    circle._x += xspeed;
    circle._y += yspeed;
    circle._y += gravity;

    // Gravity
    yspeed += gravity;

    // Timer
    update_timer += 1;

    // Wall collisions
    if (circle._x > 600) {
        circle._x = 600;
        xspeed = -xspeed;
        bounces++;
    }
    if (circle._x < 0) {
        circle._x = 0;
        xspeed = -xspeed;
        bounces++;
    }
    if (circle._y > 600) {
        circle._y = 600;
        yspeed = -yspeed;
        bounces++;
    }
    if (circle._y < 0) {
        circle._y = 0;
        yspeed = -yspeed;
        bounces++;
    }
    // Check for API events
    updateBounces();
    updateSpeed();

    // Display
    _root.speed_textfield.text = speed + " km/h";
};